Capacitance effect on the oscillation and switching characteristics of spin torque oscillators.

Tui Zeng,Peter Pt Lai,Chi Wah Leung,Philip Wt Pong,Yan Zhou

doi:10.1186/1556-276x-9-597

Abstract

We have studied the capacitance effect on the oscillation characteristics and the switching characteristics of the spin torque oscillators (STOs). We found that when the external field is applied, the STO oscillation frequency exhibits various dependences on the capacitance for injected current ranging from 8 to 20 mA. The switching characteristic is featured with the emerging of the canted region; the canted region increases with the capacitance. When the external field is absent, the STO free-layer switching time exhibits different dependences on the capacitance for different injected current. These results help to establish the foundation for capacitance-involved STO modeling.

Highlights

The conventional way of changing the magnetization of a thin film is usually realized through applying an external magnetic field
Capacitance effect [13,14,15] being introduced by intrinsic sources and extrinsic sources is
When the capacitance is in the range of 0.01 to 0.1 pF, this negative correlation is enhanced for β = −10% whereas it changes to positive correlation for β =10%

Summary

Introduction

The conventional way of changing the magnetization of a thin film is usually realized through applying an external magnetic field In recent years, it has been found both theoretically [1,2,3] and experimentally [4,5] that a spin-polarized current which carries more spin up or spin down electrons can change the magnetization when passing through the thin film. It has been found both theoretically [1,2,3] and experimentally [4,5] that a spin-polarized current which carries more spin up or spin down electrons can change the magnetization when passing through the thin film This effect helps to generate steady precession of the free-layer magnetization in a spin valve structure by an injected spin-polarized current, which results in a periodic variation of the device resistance and forms spin-torque oscillators (STOs) [6,7,8,9,10,11,12]. Capacitance effect [13,14,15] being introduced by intrinsic sources (parasitic capacitance due to the interaction between the multilayer thin films in STOs) and extrinsic sources (lead capacitance due to the connection between the external IC and STOs) is

Methods

Results

Conclusion